Pump

ABSTRACT

A pump includes an electric motor that is mounted in a motor compartment, a rotor that is mounted in a pump chamber and coaxial to a driven shaft of the motor and driven by the motor, a pump inlet nozzle, and a pump discharge nozzle, wherein the pump is enclosed by a housing and wherein the motor compartment is connected to a surrounding atmosphere by a ventilation channel. The ventilation channel is arranged parallel to the shaft of the motor in the housing and is guided from a lower end of the housing in the region of the pump inlet nozzle up to a passage opening that is formed directly underneath a motor bearing bracket.

CROSS REFERENCE

This application claims priority to German Patent Application No. 10 2013 100728.7, filed Jan. 25, 2013.

TECHNICAL FIELD OF THE INVENTION

The invention relates to a pump with an electric motor that is mounted in a motor compartment, a rotor that is mounted in a pump chamber coaxial to a shaft of the motor and can be driven by the motor, a pump inlet nozzle, and a pump discharge nozzle, wherein the pump is enclosed by a housing and wherein the motor compartment is connected to a surrounding atmosphere by a ventilation channel.

BACKGROUND OF THE INVENTION

Pumps are known and are used, in particular, in motor vehicles for feeding washing water for front windshields and/or headlamps. Pumps have the problem that they cannot be sealed in a completely liquid-tight way. This is because, when the pump is operating, the motor heats up, leading to an expansion of the air surrounding it and thus to an increase in pressure. This pressure would decrease to an equilibrium state by means of leakage in the housing that is always present in practice and can be neglected in the normal case. As soon as the motor cools down again, a low pressure is produced that is again equalized by the suctioning of air by means of the leakage in the housing. In the most unfavorable cases, water can be taken in with the air, which could lead to damage to the motor and ultimately failure of the pump. Therefore, ventilation of a motor compartment is required.

DE 1 189 641 B1 describes a pump that is enclosed by a housing. A motor compartment (interior) is ventilated by means of a line. So that water does not get into the interior when the pump is immersed in water, a pre-chamber with a volume dimensioned so that water cannot get into the line is arranged on an outer end of the line. This volume is relatively large, so that the pump is expensive to produce overall and requires a relatively large amount of package space.

From DE 44 12 210 C2, a pump is known in which a plurality of air chambers is arranged between a motor and a rotor that can be driven by this motor. The air chambers are connected on one side to a motor compartment (motor chamber) and on the other side to the surrounding atmosphere. The pump should be better protected from splash water. However, when the pump is immersed in water, there is no waterproof sealing of the motor compartment.

In DE 198 46 755 B4, a pump is disclosed in which a ventilation line for a motor compartment has a labyrinth-like construction, in order to guarantee splash-water protection. However, even in this pump, there is no waterproof sealing of the motor compartment when the pump is immersed in water.

Therefore, the problem of the invention is to create a pump that is protected in a simple way against the penetration of water and, in general, from splash water in a motor compartment up to a specified immersion depth and requires the smallest possible package space.

SUMMARY OF THE INVENTION

The ventilation channel is arranged parallel to the shaft of the motor in the housing and is guided from a lower end of the housing in the region of the pump inlet nozzle up to a passage opening that is formed directly underneath a motor bearing bracket. The ventilation channel thus forms a kind of pre-chamber, with water being able to penetrate into this pre-chamber without causing damage to the pump. The pump is designed, in particular, for installation in a motor vehicle in which its longitudinal axis—i.e., also a shaft of the motor—is arranged approximately vertical and the pump inlet nozzle points downward. In this way, an outer end of the ventilation channel, that is, the end that is allocated to the surrounding atmosphere, is arranged at its lowermost position. Thus, on one hand, any splash water is led to the outside by the force of gravity.

On the other hand, when the pump is immersed in water, the water is forced into the ventilation channel. In this way, air located in the motor compartment and in the ventilation channel is compressed so that a back pressure is created by the air. The water can rise in the ventilation channel only so far until an equilibrium state is created between the outside water pressure and the air pressure in the motor compartment and the ventilation channel. Due to the relatively large length of the ventilation channel, in ordinary operation of the motor vehicle, this state of equilibrium occurs before the water column in the ventilation channel reaches the passage opening; this is dimensioned so that damage to the motor is prevented at a maximum permissible immersion depth of the motor vehicle.

This applies accordingly for large water drops that fill the cross section of the ventilation channel.

In one construction, a cylindrical part of the housing is formed integrally with a base, the pump inlet nozzle, and the pump discharge nozzle. This simplifies the production and sealing of the housing.

In another construction, a cover of the housing is sealed in a waterproof manner with the cylindrical part. This is simple to implement and guarantees the necessary waterproof seal and stability of the housing.

In another construction, a connector for an electrical connection of the pump is arranged integrally with the cover on the cover. This further simplifies the production and sealing of the pump.

These aspects are merely illustrative of the innumerable aspects associated with the present invention and should not be deemed as limiting in any manner. These and other aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made more particularly to the drawings, which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views.

FIG. 1 is a longitudinal section through a pump,

FIG. 2 is a cross section 2-2 through the pump of FIG. 1,

FIG. 3 is a side view of the pump, partially in section, and

FIG. 4 is a view of the bottom side of the pump.

DETAILED DESCRIPTION

In the following detailed description numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, the invention is not limited in scope to the particular type of industry application depicted in the figures. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

As can be seen from FIGS. 1 to 4, a pump comprises a housing 1 on which a pump inlet nozzle 2 and, in a lower region tangentially spaced apart from the inlet nozzle, a pump discharge nozzle 3 are formed integrally on a lower end—with respect to the views in FIGS. 1 and 3 and also in the installation in a motor vehicle. The housing 1 has an essentially cylindrical part 1 a with circular cross section; thus it is rotationally symmetric, with the exception of the pump discharge nozzle 3 and a ventilation channel 4 that is formed outside on the housing parallel to a longitudinal axis of the housing 1. The housing 1 is closed on the lower end by a base 1 b that is formed integrally with the cylindrical part 1 a, wherein the pump inlet nozzle 2 with an inlet opening is formed axially spaced apart on the base 1 b. The housing 1 has an essentially pot-shaped construction.

In the lower area of the housing 1, a pump chamber 5 is formed in which a rotor 10 is supported so that it can rotate. A motor compartment 6 in which an electric motor 7 is mounted is arranged above the pump chamber 5. The pump chamber 5 is hermetically separated from the motor compartment 6 by a seal 8, wherein a shaft of the motor 7 passes through the seal and is provided with special sealing means. The rotor 10 is mounted on one end of the shaft so that it can be driven.

The housing 1, the motor 7, the rotor 6, and the pump inlet nozzle 2 are oriented coaxial to each other, so that the longitudinal axis of the housing 1 is identical to the longitudinal axis of the pump.

The housing 1 is closed in a waterproof manner by a cover 8 at its upper end. A connection 9 to contact pins for the electrical connection of the motor 7 is arranged on a top side of the cover 8. The cover 8 is welded, e.g., with the housing 1, wherein both the water-proof sealing and also the mechanical stability are guaranteed. At the same time, the cover is used for fixing a motor bearing bracket 7 a that is arranged on an upper end of the motor 7 and thus for fixing the motor 7.

The ventilation channel 4 is formed on the outside on the cylindrical part 1 a of the housing 1 between a double wall arranged here. It extends parallel to the longitudinal axis of the pump between the lower area of the cylindrical part 1 a at the height of the pump chamber 5 and a passage opening 11. The latter represents an air-permeable connection between the motor compartment 6 and the ventilation channel 4 and is arranged directly underneath the motor bearing bracket 7 a. The double wall is formed on the inside by a section of the cylindrical part la and on the outside by a wall formed onto this part, wherein the ventilation channel is arranged in-between, that is, within the double wall. A cross section of the wall forms a circular section. A radius of the circular section is smaller than the cylindrical part 1 a, so that the cross section of the ventilation channel 4 has a sickle-shaped construction. The width of the sickle shape tapers slightly from the top to the bottom.

The housing 1 with the pump inlet nozzle 2, the pump discharge nozzle 3, and the double wall of the ventilation channel 4 on one side and the cover 8 with the connector 9 on the other side are made from plastic, e.g., in an injection molding process.

For the installation in the motor vehicle, the pump is mounted on an upper wall of a water container in which the pump inlet nozzle 2 is pressed up to the limit stop in an opening provided for this purpose. This opening is provided with a sealing ring that fixes the pump in a clamping manner by a friction fit and provides for the necessary waterproof sealing. The pump inlet nozzle 2 extends into the immediate vicinity of the container base.

The container with the pump is then mounted in the motor vehicle. In this way, the longitudinal axis of the motor is oriented approximately in the vertical direction. A compressed air hose and an electrical connection cable with connector are connected.

The preferred embodiments of the invention have been described above to explain the principles of the invention and its practical application to thereby enable others skilled in the art to utilize the invention in the best mode known to the inventors. However, as various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by the above-described exemplary embodiment, but should be defined only in accordance with the following claims appended hereto and their equivalents.

LIST OF REFERENCE SYMBOLS

1 Housing

1 a Cylindrical part

1 b Base

2 Pump inlet nozzle

3 Pump discharge nozzle

4 Ventilation channel

5 Pump chamber

6 Motor compartment

7 Motor

7 a Motor bearing bracket

8 Cover

9 Connector

10 Shaft

11 Passage opening 

1. A pump comprising: an electric motor that is mounted in a motor compartment, a rotor that is mounted in a pump chamber coaxial to a shaft of the motor and can be driven by the motor, a pump inlet nozzle, a pump discharge nozzle, wherein the pump is enclosed by a housing and wherein the motor compartment is connected to a surrounding atmosphere by a ventilation channel, and wherein the ventilation channel is arranged parallel to the shaft of the motor in the housing and is guided from a lower end of the housing in the region of the pump inlet nozzle up to a passage opening that is formed directly underneath a motor bearing bracket.
 2. The pump according to claim 1, wherein a cylindrical part of the housing is formed integrally with a base, the pump inlet nozzle, and the pump discharge nozzle.
 3. The pump according to claim 2, wherein a cover of the housing is sealed in a waterproof manner with the cylindrical part.
 4. The pump according to claim 3, wherein a connector for an electrical connection of the motor is arranged integrally on the cover. 